Carbureter



J. T. ROFFY.

CARBURETEH.

APPLICATION HLED JUNE I. 1911'.

Patented Apr. 27, 1920.

INVENTOR 0 w w n 5W6 9 3 WB MHW W i 2 Z. q a e w w w 4 5 3 WW M 1 3 n w/vx xf/ M 9 3 0 fl/ 3 3 4 3 w 5 a. M I 7 a J 7 l 8 r .8

WITNESSES mixtures UNITED STATES PATENT OFFICE.

JOSEPH T. ROFFY, OF PITTSBURGH, PENNSYLVANIA.

CARD URE'I' ER.

Application filed June 11,

To all 'whomit may concern.-

Be it known that I, JOSEPH T. ROFFY, a subject of the King of Hungary, and a resident of Pittsburgh; in the county of Allegheny and State of Pennsylvania, have made a. new and useful Invention in Can bureters, of which the following is a specification.

This invention relates to carbureters and more particularly to carburetors for engines or motors for use in automotive de vices which must be flexible as regards to both speed and torque.

The efficiency of such motors demands relatively rich mixtures for maximum power and relativel lean mixtures for maximum thermal e ciency and since the quantity of mixture required for idling is roxlmately one-fifteenth of that required for volumetric elliciency the combination in a charge forming device or carbureter of at least two Venturi choke tubes or jets communicating with a common mixl l'l chamber with means for correlating the discharged from the separate choke tubes or jets is desirable.

An object of this invention is to provide a carburetor of simple construction combining two or more chargo-forming-devi'ccs, one adjusted for maximum power and one adjusted for maximum thermal efl'iciency, with means for correlating the combustible chargerr'oriucd by the two devices.

A further object is to provide in a carburetor in whiahtwo charge forming devices commuoizmtr with 8 Common mixing Cllllllb leer and in which a valve is located between one a? said devices and said chamber, suspension means For mounting said valve construcred so that said valve on its travel from cl sed-(n substantially half open posiiiou l5 increasingly rct-istfd from substantially zero resistance to maximum resistance and from said half open position to full open position is dccrcasingly resistcd from maximum resistance to substantially zero resistance at the full open position.

These as well as other objects which will readily appear to those skilled in this purticulur art are attained in the device dc= scribed in the specification and illustrated in the aucom mnying drawings forming a part of this application and throughout which like oh-nn-nts arc dcnolcd byJiko characters.

[11 thc drawings Figurev l is a uuu'c or Specification of Letters Patent.

therewith is valve 12.

Patented Apr. 27, 1920.

1917. Serial No. 173,92?

tion.

Fig. 2 is an enlarged detailed View of a portion of the device and Fig. 3 is a view partially in plan and initially in cross sec tion taken along line -"l of Fi 2 looking in the direction of the arrows. Fig. 4 is a diagrammatic view of the valve and links when the valve is half open and Fig. 5 is a similar view when the valve is fully opened.

The carburetor consists of a body portion 5 formed with two mixture passages 6 and '4'. Passage T surrounds the upper part of passage 6 as indicated by dotted line 8 and both passages (l and 7 emerge into a common mixin chamber 9 the outlet of which is controller by an ordinary butterfly throttle valve 10.

The top of passage a is formed in the nature of a valve seat ll and cooperating Valve 12 is provided with a central flanged opening 13. The bore of the flange scrving as a bcurin surface for the \dlYBJYlllll! surrounds fl-III is slidubly mounted on a. romprrssion guide 14. The uppcr end of compression guide 14 has integral arms 17 and 1b .which terminate in split yoke members 15 and 16 as best shown in Fig. 2.

A valve cover 19 threaded into an opening at the top of the carburetor body is provided with :1. depending stud 20 which passes bctwccn 'yoke mcmbers l5 and 16 and at its lower end has integral yokes 21 and 22. The upper yokcs l5 and 16' and the lower yokes 2t and 22 are connected togcther by means of pairs of links 23 and 24-.

pair of these links are links 27 which are pix oi ally connccted to cars 2 8 formed interal with the valve 12. Compression memer 1-]: is bored out to receive a hollow guide pin 30 which is slidable within said here and which at its lower end is enlarged as at 31 to receive the enlarged end of a. flexible cable 32 forming part of a Bowden wire", the cover portion of which is secured to,t he vulvc cover at 33.

Tnterposed between a collar 3-1 formed on compression member H and the enlarged end 31 of guide 30 is a compression spring 35.

'lhc lower cud of spring 35 is udjustably supportcd by cable 3). and the end 31 of Mounted on thepius 25 connecting each" guide pin 30,-and the springs extension tendency is exerted upwardly against the compression guide 14: wh'ch is held by links 23 and 24 against upwarzkmovement beyond the position shown in Fi 1. As valve 12 is lifted from its seat, each link 27 breaks the toggle joint formed by its cooperating links and forces pin 25 inwardly which pulls yokes 15 and 16 downwardly against the increasing resistance of spring 45. While the spring resistance is increasing, the effective. length of the lever formed by link 27 is decreasing until, when the parts reach the position shown in Fig. 5, its effective length is zero and the valve seating device may be said to be on a dead center and the only seating force is the gravitational pull on valve 12 and little or no effort is required to hold the valve in full open position.

In the position shown in Fig. 1, valve 12 may be said to be at its lower dead center for links 23 and 24 are in line, one with the other. When the valve 12 reaches the limit of its upper [J'ztflfl and pins 25 have moved inward to their inner limits of travel, valve 12 ma be said to be at its upper dead center or links 27 will then be in the same horizontal plane. By roper design and adjustment the point 0 greatest resistance to the valves 3 may be varied. I refer to have it at the point indicated in ig. 4 whence the valve in moving from its closed to its wide open position will be resisted by spring 35 but the resistance'to movement gradually increases from substantially zero resistance at closed position to maximum resistance at half open osition and the resistance decreases 'rom maximum resistance to substantially zero at full open position.

By com ressing spring 35 more or less through tlie BOWdQILWlIB which may be connected so as to be manually operated, valve 12 may be loaded more or less to resist opening movement without aifecting the valve in its two extreme positions, full closed and full open.

The carburetor. body terminates at its bottom end in an internally threaded member 36, and the lower part of the walls forming each of the passages 6 and 7 is faced to receive a Venturi choke tube. 1

The carbureter base 37 carrying liquid fuel nozzles 38 and 39 is secured against member 36 by means of a stud 40 threaded into said member. The base is formed so as to secure Venturi choke tubes 41 and 42 in place. Liquid nozzles 38 and 39 through chann ls 43 and 44 may be connected with a sing float chamber of usual construction. not shown, or each may be connected with a separate float chamber if it is desired to use two fuels of different inflammability for the carbureter.

If one fuel is to be used the charge-form ing-de'vice made up of fuel nozzle 39, Venturi choke tube 41 and mixture passage 6 will be termed the major charge-formingdevice, and the device comprising .liquid nozzle 38, Vcnturi choke tube 42 and llllX turc passage 7 will be termed the minor charge-forming-device.

If two fuels are used such as gasoleuc and kerosene the same churgc-forming-dcvice will still he the major and utilize the kerosene or other not .readily inflammable fuel, and the smaller device will be the minor and will use the gasolenc or some read ily inflammable fuel.

A housing 45 formed in the nature of a stamping having an inlet opening 46 is held in contact with the base portion of the carbureter by means of a nut 47 threaded onto a depending portion 48 of stud 40.

Operation.

-rectify the total charge handled by admittin air.

'1 he mechanism for operating the valve is one having a modulating reaction. A further rise of vacuum in the mixing chamber will be followed by a relatively greater opening of the valve corresponding to the tendency to an enrichment of the minor venturi.

The capacity of the minor venturi thus reached, the air velocity, in the major venturi is now sufficient to detach fuel from the main jet. At this stage we have a relatively rich mixture from the minor venturi augmented by a lean mixture from the major venturi.

The vapor velocity in each venturi will depend upon the ratio between the area of the end of its respective passage, 6 or 7, and the area 'of its respective choke tube, 41 or 42. I prefer to provide equal ratios between the respective areas and therefore maintain equal velocities through the two venturies when valve 12 is wide open. Whatever the i'elationbetween the two velocities may be, the construction of my device makes that relation constant so long as the maximum throttle opening is used even though there be slight variations in the vacuum created in the mixing chamber.

It will thus be apparent that the low speed is dependent upon the size of the minor venturi and its jet orifice and that the extreme high on the size of the major venturi and its jet orifice. Further, that if the minor venturi is ad' twelve to one air an fuel ratio, conceded to be that for maximum power, and the major venturi is adjusted with a 'et orifice for a seventeen to one air and fuel ratio, conceded to be that for maximum thermal efiiciency, then the transition from maximum power air and fuel ratio to maximum thermal efficiency air and fuel ratio depends uponthe reactlon of the modulating valve.

B y adjusting valve cover 19 to different vertical positions, the valve and its operating mechanism may be shifted'to different vertical positions, thereby obtaining the proper idling adjustment of the carbureter.

It will be understood that if desired, liquid jets 38 and 39 may be provided with needle valve adjustments, although under most circumstances this is not considered necessary.

In accordance with the provisions of the patent statutes, I have described the principle of operation of my invention, together with the device which I now consider to represent the best embodiment thereof, but I desire to have it understood that the device shown is only illustrative and that the invention can be carried out in other ways within the scope of the appended claims.

What I claim is:

1. In a carburetor in which two charge forming devices communicate with a common mixing chamber and in which a valve is located between one of said devices and said chamber, means for mounting said valve constructed so that said valve in its travel from closed to substantially halfopcn position is increasingly resisted from substantially zcro resistance to maximum resistance and from said half open position to full open position ,is decreasingly resisted to substantially zero resistance at full open position.

2. Ina carburetor in which two charge forming devices communicate with a common mixing chamber and in which a. valve is located between one of said devices and said chamber, means for mounting said valve including links connected to the valve and a member axially alined with said valve to which said links are in turn connected through other links.

3. In a carbureter in which two charge forming devices communicate with a common mixing chamber and in which a valve is located between one of said devices and said chamber, valve mounting means comprising toggle means and a spring for controlling the operation of the toggle means.

usted with a jet for a 4. In a carburetor in which two charge forming devices communicate with a common mixing chamber and-in which a valve is located between one of said devices and said chamber, means for mounting said valve comprising toggle mechanism and a spring so arranged with relation to the toggle as to cause said mechanism to exert an increas ing resistance to movement of the valve from closed to half open position and a decreasing resistance from half to full open position.

5. In a carburetor in which two charge forming devices communicate with a common mixing chamber and in which a valve is located between one of said devices and said chamber, means for mounting said valve comprising two toggle mechanisms operating in parallel and arranged to resist movement of the valve. I

6. In a carbureter in which two charge forming devices communicate with a common mixing chamber and in which a valve is located between one of said devices and said chamber, means for mounting said valve comprising a hollow stem or post upon which said valve is mounted to slide, a fixed support above said valve, a member sliding on said post, toggle mechanism connecting said support, said member and said valve, and a spring for adjustabl loading said valve.

7. In a carbureter in which two charge forming devices communicate with a common mixing chamber and in which a valve is located between one of said devices and said chamber, valve comprising a hollow stem or. 0st upon which said valve is mounted to s ide, a fixed support above said valve, a member sliding on said post, toggle mechanism connecting said support, said member and said valve, a spring and means whereby the tension of said spring may be remotely controlled.

8. In a carbnreter in which two charge forming devices communicate with a common mixing chamber and in which a valve is located between one of said devices and said chamber. means for mounting said valve comprising a hollow post upon which said valve is mounted to slide, a support member slidable on said post, a spring resisting movement of said member toward the valve, a fixed member, a tog le mechanism between said fixed and sli ing members and links connecting said valve to the fulcrum of said toggle mechanism.

In testimony whereof, I have hereunto subscribed my name this 7th day of June,

JOSEPH T. R-OFFY. lVitnesses: JNo. S. GREEN, EMMA LEA MONTGOMERY.

means for mounting said 

